Question

First animals that were triploblastic and showed bilateral symmetry and organ level of organisation were a part of:

• A. Phylum Ctenophores
• B. Phylum Aschelminthes
• C. Phylum Platyhelminthes
• D. Phylum Cnidaria

Answer 1

The correct option is C Phylum Platyhelminthes

Animals belonging to the phylum Platyhelminthes were the first to have three germ layers (triploblastic) and show bilateral symmetry and organ level of organisation. They have specialised organs for excretion such as flame cells. Nerve cords form the nervous system.